Three years after the attack on London, Jim has overcome the psychological effects of his resurrection and is one of Starfleet's most respected captains. A brief leave on Earth for his brother's wedding reunited him with an old friend, and Jim is left to consider whether a ship alone is enough to make him happy.

The Nexus releases Kirk in the year 2254, but he soon realizes that this isn't his universe. Too many things are different, so many details are wrong. He prepares to face the future alone—until he's reunited with an old friend.

Spock has just graduated with highest honors from the Vulcan Science Academy when Nero destroys his planet. Lucky to escape with his life, he is bound for Earth on a rescue ship where he meets a strange fellow traveler: an elder version of himself. Disturbed by his counterpart's experiences in his own timeline, Spock vows never to follow the desires of his human half. But when a man named Jim Kirk comes into Spock's life, he's faced with a struggle to find the balance between Vulcan and human.

When Spock contracts a rare life-threatening disease, Jim rushes to Vulcan to care for him. Concerned about possible biological warfare, Starfleet sends McCoy for answers. But when Jim starts displaying symptoms of a disease which should only be fatal to Vulcans, the search for the real culprit begins.

Dual tragedies bring the Enterprise's command team closer together, but the gap between them grows when Spock discovers something in Jim's mind. This is a story about falling in love, falling apart, and falling back together.